The effect of petroleum hydrocarbons concentration on competition between oil-degrading bacteria and indigenous compost microorganisms in petroleum sludge bioremediation

The influence of the concentration total petroleum hydrocarbons (TPHs) on competition between isolated oil-degrading bacteria (ODB) and finished compost microorganisms (FCM) was investigated in composting bioreactors over 12 weeks period. First, batch tests were performed Bushnell–Haas medium (BHM) to evaluate biodegradation activities six native ODB from sludge (PS). Then, added containing 10 30 g/kg TPHs. Based BHM results, highest degradation efficiency crude oil (1%–3% concentration) determined be 72%–75% at pH 7 after days. In only ODB, TPHs removal rates 86%–92% weeks. Although lower (73%–89%) both FCM indicated a slight them, still effective presence especially greater concentrations Despite fact that addition (FC) PS changed microbial composition bioreactors; populations exhibited little variation during process. This study alone or FCM, effectively degraded